 |
|
Title
|
|
Crystallization and preliminary X-ray crystallographic study of the Ras-GTPase-activating domain of human p120GAP.
|
|
|
Authors
|
|
K.Scheffzek,
A.Lautwein,
A.Scherer,
S.Franken,
A.Wittinghofer.
|
|
|
Ref.
|
|
Proteins, 1997,
27,
315-318.
|
|
|
PubMed id
|
|
|
|
|
|
Abstract
|
|
|
Ras-GTPase-activating proteins (Ras-GAPs) are important regulators of the
biological activity of Ras within the framework of intracellular communication
where GTP-bound Ras (Ras:GTP) is a key signal transducing molecule (Trahey and
McCormick, Science 238:542-545, 1987; Boguski and McCormick, Nature 366:643-654,
1993). By accelerating Ras-mediated GTP hydrolysis, Ras-GAPs provide an
efficient means to reset the Ras-GTPase cycle to the GDP-bound 'OFF'-state and
terminate the Ras-mediated signal. Here we report the crystallization of the
GTPase-activating domain of the human p120GAP. The crystals-belong to the
orthorhombic space group symmetry P2(1)2(1)2(1) with unit cell dimensions of a =
42.2 A, b = 55.6 A, c = 142.2 A, alpha = beta = gamma = 90 degrees. Assuming a
Matthews parameter of 2.2 A3/Da, there is one molecule per asymmetric unit.
Applying micro-seeding techniques, we grew large single crystals that could not
be obtained by other routine methods for crystal improvement. They diffracted to
a resolution of approximately 3 A using X-rays from a rotating anode generator
and to better than 1.8 A in a synchrotron beam. Chemical cross-linking led to
reduction of the maximum resolution but to significantly increased stability
against mechanical and heavy atom stress.
|
|
|
|